Swarming And Varroa Infestation

In an interview on a German podcast about a year ago, Dr.Tom Seeley made some interesting points during the interview that I, as a self-proclaimed “Organic” beekeeper find very interesting and supporting of some of the points I often make in my own presentations and classes.

This isn’t to say that Dr. Seeley is an Organic beekeeper or that he claims to be, but from a research point of view he has made certain observations which to my mind, certainly seem to support some Organic beekeeping ideas.

One of the points Organic beekeepers make is that when at all possible, we want to mimic or emulate successful practices and behaviors of honey bee colonies that are feral or wild as opposed to doing things that might work contrary to “bee nature”.

Honey bee swarm in a tree. Image by Tony Sandoval

In this particular discussion, Dr. Seeley makes the point that swarming in a honey bee colony can actually have a positive effect on reducing Varroa mite populations in the nest.  This is accomplished primarily due to the exit of the large number of adult bees during the Primary swarm.  It is further impacted by the consequent lack of eggs being laid and there being a period of being brood-less in the hive in between the exit of the prior mature Queen and the beginning of the new mature queen beginning to lay eggs.

All in all, Dr. Seeley says that when a colony is allowed to swarm naturally, approximately 60 to 70% of all the adult bees in the hive depart with the prime swarm.  That number is a result of the facts that about 50% of mites are phoretic, meaning that they are parasitize adult bees instead of being in cells parasitizing larvae and capped pupae.  Of all those approximately 35% of all mites are removed from the nest because of the departing swarm.

File:Varroa destructor on the head of an emerging bee (5048710240).jpg
Varroa destructor on the head of an emerging bee By Gilles San Martin from Namur, Belgium [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons
There can be a further reduction in mite population after a prime swarm departure due to the exit of after swarms, grooming behavior of remaining bees and lack of bees to parasitize due to not enough bees remaining to sustain a population of mites.

In terms of Organic hive management, this supports the practice of preferring to do splits in the Spring and Fall to reduce mite populations as opposed to using chemical treatments be they toxic or non-toxic chemicals.

Another interesting comment he made was that the practice of beekeeping by humans is contrary to the natural evolution of honey bee colonies which have evolved to excel in two areas due to Natural Selection.  Those two things being survival and reproduction which obviously go hand in hand.Beekeeping by people, by and large according to Dr. Seeley actively works to inhibit reproduction and suppress swarming.

Beekeepers tend to try to control reproduction and inhibit it by controlling drone populations (one of the common methods of controlling Varroa) and by inserting already fertilized, inseminated queens.  In regards to suppressing swarming, it is a common practice among beekeepers to manipulate hive boxes, especially in the Spring, to try to minimize or eliminate the chances of colonies swarming out so as to keep the hive population large for obtaining a larger honey harvest over the season.

Suppressing swarming is also a method used by many beekeepers as a way to try to keep larger populations inside the hives, thereby keeping more bees present to “work” the nest and keep pest populations down through the bees own nest behaviors.

It’s certainly some interesting information from a very well-respected and trusted bee researcher.  Even if one doesn’t consider themselves an Organic beekeeper, the knowing how swarms affect Varroa populations in the hive can certainly bee good to know about.

Listen to the “Radio Milkwood”podcast for more of the roughly 12 minute interview with Dr. Tom Seeley.

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